diff --git a/src/named_systems2.jl b/src/named_systems2.jl
index b96a88d6..516e3a07 100644
--- a/src/named_systems2.jl
+++ b/src/named_systems2.jl
@@ -864,6 +864,8 @@ end
 
 names2indices(::Colon, allnames) = 1:length(allnames) 
 
+names2indices(inds::Union{Integer, AbstractVector{<:Int}}, allnames) = inds
+
 function names2indices(names, allnames)
     inds = Union{Nothing, Int}[findfirst(==(n), allnames) for n in names]
     snames = string.(allnames)
@@ -980,6 +982,10 @@ function partition(P::NamedStateSpace; u=nothing, y=nothing,
         y = setdiff(1:P.ny, inds)
         z = inds
     end
+    u = names2indices(identity.(u), P.u)
+    y = names2indices(identity.(y), P.y)
+    z = names2indices(identity.(z), P.y)
+    w = names2indices(identity.(w), P.u)
     u = vcat(u)
     y = vcat(y)
     z = vcat(z)
diff --git a/test/test_named_systems2.jl b/test/test_named_systems2.jl
index 20a9b95b..869b2fdd 100644
--- a/test/test_named_systems2.jl
+++ b/test/test_named_systems2.jl
@@ -43,6 +43,10 @@ s3 = named_ss(G3, x = :x, u = :u, y=:y, z=:z, w=:w)
 @test length(s3.u) == 3
 @test length(s3.y) == 2
 
+s3part = partition(s3, y=:y, z=:z, w=:w, u=:u)
+@test s3part == G3
+@test performance_mapping(s3part) == s3[:z, :w].sys
+
 # Test prefix matching
 G4 = ControlSystemsBase.ssrand(1,2,3)
 s4 = named_ss(G4, x = :x, u = [:u1, :u2], y=[:y])